ext3: Fix fs corruption when make_indexed_dir() fails

When make_indexed_dir() fails (e.g. because of ENOSPC) after it has allocated
block for index tree root, we did not properly mark all changed buffers dirty.
This lead to only some of these buffers being written out and thus effectively
corrupting the directory.

Fix the issue by marking all changed data dirty even in the error failure case.

CC: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>